Lens barrel

ABSTRACT

A lens barrel includes a first frame and a second frame. The first frame includes a plurality of cam grooves. The second frame includes a plurality of cam followers that engage with each of the plurality of cam grooves, and a gear portion. In this case, if rotational force is transmitted to the gear portion, the second frame moves in the optical axis direction while rotating with respect to the first frame. At least one of the plurality of cam followers is disposed on the image plane side of the gear portion.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of PCT Application PCT/JP2012/000381, with aninternational filing date of Jan. 23, 2012 which claims priority toJapanese Patent Application No. 2011-012398 filed on Jan. 24, 2011. Theentire disclosures of PCT Application PCT/JP2012/000381 and JapanesePatent Application No. 2011-012398 are hereby incorporated herein byreference.

BACKGROUND

1. Technical Field

The technology disclosed herein relates to a lens barrel that supportsan optical system.

2. Background Information

There are known lens barrels that support an optical system with whichthe focal distance can be varied. For example, the lens barrel disclosedin Japanese Laid-Open Patent Application 2007-219304 comprises a firstmoving cam ring in which a cam groove is formed, and a first group lensbarrel that supports a first lens group. The first group lens barrel hasa follower pin that engages in the cam groove. With this lens barrel,the first moving cam ring and the first group lens barrel allow thefirst lens group to be moved in the optical axis direction with respectto the first moving cam ring.

A gear for driving with a motor or the like is formed on the outerperiphery of a frame used in this type of lens barrel. Also, a pluralityof cam followers are often formed on the frame to which the gear isprovided.

However, when a gear and a plurality of cam followers are provided tothe same frame, the gear is disposed between the cam followers, but withthis layout, the length of the gear is limited by the cam followers, sothe rotational angle of the frame cannot be increased. When increasingthe zoom ratio of the lens barrel is taken into account, it ispreferable to have a larger rotational angle of the frame.

It is an object of the technology disclosed herein to provide a lensbarrel with which the zoom ratio can be increased.

SUMMARY

The lens barrel disclosed herein comprises a first frame and a secondframe. The first frame includes a plurality of cam grooves. The secondframe includes a plurality of cam followers that engage with each of theplurality of cam grooves, and a gear portion. In this case, ifrotational force is transmitted to the gear portion, so that the secondframe moves in the optical axis direction while rotating with respect tothe first frame. At least one of the plurality of cam followers isdisposed on the image plane side of the gear portion.

With this lens barrel, since at least one of the plurality of camfollowers is disposed on the image plane side of the gear portion of thesecond frame, the gear portion can be longer in the peripheraldirection. Therefore, when the gear portion is used to rotationallydrive the second frame with respect to the first frame, large relativerotational angles can be ensured for the first frame and the secondframe. When the relative rotational angles of the first frame and secondframe are thus increased, the amount of movement of the second framewith respect to the first frame can be increased. That is, the zoomratio can be raised with this lens barrel.

With the technology disclosed herein, a lens barrel can be provided withwhich the zoom ratio can be raised.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the attached drawings, which form a part of thisoriginal disclosure:

FIG. 1 is an oblique view of a digital camera 1 equipped with a lensbarrel;

FIG. 2 is an oblique view of when the lens barrel is retracted;

FIG. 3 is an oblique view of when the lens barrel is used for imaging;

FIG. 4 is an exploded oblique view of a lens barrel;

FIG. 5 is a detail enlargement of FIG. 4;

FIG. 6 is a detail enlargement of FIG. 4;

FIG. 7 is a development view of a fixed frame;

FIG. 8A is a simplified cross section of when the lens barrel isretracted, and FIG. 8B is another simplified cross section of when thelens barrel is retracted;

FIG. 9A is a simplified cross section of when the lens barrel is at thewide angle end, and FIG. 9B is another simplified cross section of whenthe lens barrel is at the wide angle end;

FIG. 10A is a simplified cross section of when the lens barrel is at thetelephoto end, and FIG. 10B is another simplified cross section of whenthe lens barrel is at the telephoto end;

FIG. 11 is an oblique view of a cam frame;

FIG. 12 is an oblique view of a cam frame;

FIG. 13 is an oblique view of a cam frame;

FIG. 14 is a development view of when a second cam groove and anauxiliary groove are retracted;

FIG. 15 is a development view of when a second cam groove and anauxiliary groove are at the wide angle end;

FIG. 16 is a development view of when a second cam groove and anauxiliary groove are at the telephoto end;

FIG. 17 is an oblique view of a second rectilinear frame;

FIG. 18 is an oblique view of a second rectilinear frame;

FIG. 19A is a side view of the second rectilinear frame, and FIG. 19B isa side view of the second rectilinear frame;

FIG. 20 is an oblique view of a first lens frame;

FIG. 21 is an oblique view of the state when the first lens frame and abarrier unit have been assembled;

FIG. 22A shows the positional relation between the cam frame and thebarrier unit in a stowed state, and FIG. 22B shows the positionalrelation between the cam frame and the barrier unit in a deployed state;

FIG. 23A is a cross section along the XXIVA-XXIVA line in FIG. 22A, andFIG. 23B is a cross section along the XXIVA-XXIVA line in FIG. 22B;

FIG. 24A illustrates the assembly of the cam frame and the secondrectilinear frame in an insertion state, and FIG. 24B illustrates theassembly of the cam frame and the second rectilinear frame in a rotationstate; and

FIG. 25 is a simplified cross section of the lens barrel (stowed state).

DETAILED DESCRIPTION OF EMBODIMENTS

Selected embodiments of the present technology will now be explainedwith reference to the drawings. It will be apparent to those skilled inthe art from this disclosure that the following descriptions of theembodiments of the present technology are provided for illustration onlyand not for the purpose of limiting the technology as defined by theappended claims and their equivalents.

<Simplified Configuration of Digital Camera>

As shown in FIG. 1, the digital camera 1 comprises a housing 2 and alens barrel 100 (an example of a lens barrel). When a power switch 10 isused to turn on the power, the lens barrel 100 is deployed from thehousing 2 so that imaging is possible.

The digital camera 1 shown in FIG. 1 is an example of an imaging device.The imaging device may be a digital camera or a film camera. Also, theimaging device may be a camera with which the lens barrel 100 can beremoved and exchanged. The imaging device may also be a still camerathat primarily captures still pictures. Or, the imaging device may be avideo camera that primarily captures moving pictures.

For the sake of description, the subject side of the digital camera 1will hereinafter be defined as the forward or front side, and the userside as the rearward or back side. The vertically upper side when thedigital camera 1 is in its landscape orientation will be defined as thetop side, and the vertically lower side when the digital camera 1 is inits landscape orientation will be defined as the bottom side. The rightside as viewed from the subject side will be defined as the right side,and the left side as viewed from the subject side will be defined as theleft side. The “landscape orientation” here is an orientation in whichthe long-side direction of a CCD image sensor 110 is parallel to thehorizontal direction, and the short-side direction of the CCD imagesensor 110 is parallel to the vertical direction. Herein, a directionparallel to the optical axis AX of the optical system O will sometimesbe called the optical axis direction.

<Overall Configuration of Lens Barrel>

As shown in FIGS. 1 and 2, when the power to the digital camera 1 isoff, the lens barrel 100 is in its stowed state. In the stowed state,the plurality of frames of the lens barrel 100 are pulled back into thehousing 2. In this state, the lens barrel 100 is smaller in size in theoptical axis direction. On the other hand, when the power to the digitalcamera 1 is on, as shown in FIG. 3, the lens barrel 100 is in a state inwhich imaging is possible (also called an initial imaging state). In theinitial imaging state, the plurality of frames of the lens barrel 100are deployed from the housing 2. In this state, the lens barrel 100 islarger in size in the optical axis direction than in the stowed state.

As shown in FIGS. 4 to 6, the lens barrel 100 comprises the opticalsystem O, a lens drive mechanism 111, and the CCD image sensor 110.

The optical system O forms an optical image of a subject on the lightreceiving face of the CCD image sensor 110. As shown in FIG. 4, theoptical system O has a first lens group G1 (an example of a lenselement), a second lens group G2, and a third lens group G3. As shown inFIG. 5, the first lens group G1 has a first lens L1 and a second lensL2. The second lens group G2 is a blur correction lens group. As shownin FIG. 6, the second lens group G2 has a third lens L3, a fourth lensL4, a fifth lens L5, and a sixth lens L6. The third lens group G3 has aseventh lens L7 that functions as a focus lens.

The above-mentioned lens barrel 100 drives each of the first lens groupG1, the second lens group G2, and the third lens group G3 in the opticalaxis direction. The lens barrel 100 varies the focal distance of theoptical system O by changing the spacing between the first lens group G1and the second lens group G2 and the spacing between the second lensgroup G2 and the third lens group G3. Varying the focal distance iscalled zooming.

The lens barrel 100 varies the imaging distance (also called the subjectdistance) from the digital camera 1 to the main subject that is infocus, by moving the third lens group G3 in the optical axis direction.Varying the imaging distance is also called focusing. The configuration(number and shape) of the various lenses of the optical system O is notlimited to that in this embodiment, and other configurations may be usedinstead.

The CCD image sensor 110 converts an optical image of a subject into anelectrical image signal. The CCD image sensor 110 is fixed to a masterflange 109 of the lens drive mechanism 111 (discussed below). The CCDimage sensor 110 is an example of an imaging element. The imagingelement may instead be a CMOS image sensor, for example.

The first lens group G1, second lens group G2, and third lens group G3are driven by the lens drive mechanism 111. The lens drive mechanism 111will now be described in detail.

Lens Drive Mechanism

As shown in FIGS. 4 to 6, the lens drive mechanism 111 comprises a firstlens frame 101, a first rectilinear frame 102, a cam frame 103, a secondrectilinear frame 104, a second lens frame 105, a shutter unit 106, afixed frame 107, a third lens frame 108, and the master flange 109.

The first lens frame 101 supports the first lens group G1. The secondlens frame 105 supports the second lens group G2. The third lens frame108 supports the third lens group G3. The first lens frame 101, thesecond lens frame 105, and the third lens frame 108 are driven in theoptical axis direction with respect to the fixed frame 107. The camframe 103 rotates with respect to the fixed frame 107 and the masterflange 109. The first lens frame 101, the first rectilinear frame 102,the second rectilinear frame 104, the second lens frame 105, the shutterunit 106, and the third lens frame 108 do not rotate with respect to thefixed frame 107 or the master flange 109.

(1) Fixed Frame 107

The fixed frame 107 is a substantially cylindrical member. In the stowedstate shown in FIG. 2, the first lens frame 101, the first rectilinearframe 102, the cam frame 103, the second rectilinear frame 104, thesecond lens frame 105, the shutter unit 106, and the third lens frame108 are stowed in the fixed frame 107.

As shown in FIG. 6, the fixed frame 107 rotatably supports a drive gear114. The drive gear 114 is able to rotate with respect to the fixedframe 107, around a rotary shaft disposed parallel to the optical axisAX. A plurality of attachment portions 115 are formed on the outerperipheral part of the fixed frame 107. The lens barrel 100 is attachedto the housing 2 via the attachment portions 115. The attachmentportions 115 are screwed to the housing 2, for example.

The master flange 109 is fixed to the fixed frame 107. Morespecifically, screw bosses are formed on the fixed frame 107. The masterflange 109 is fixed to the fixed frame 107 by screws and the screwbosses of the fixed frame 107.

A zoom motor unit 116 is fixed to the fixed frame 107. The zoom motorunit 116 rotationally drives the cam frame 103 through the drive gear114.

As shown in FIG. 7, the fixed frame 107 has three first cam grooves112A, 112B, and 112C, and six rectilinear guide grooves 113. The firstcam grooves 112A, 112B, and 112C and the rectilinear guide grooves 113are formed in the inner peripheral face of the fixed frame 107. Thefixed frame 107 supports the cam frame 103 via the first cam grooves112A, 112B, and 112C. The fixed frame 107 also supports the firstrectilinear frame 102 via the rectilinear guide grooves 113. Therectilinear guide grooves 113 restrict the rotation of the firstrectilinear frame 102, and extend in the optical axis direction.

(2) Cam Frame 103

As shown in FIG. 5, the cam frame 103 (an example of a drive frame) isprovided to drive the first lens frame 101 and the shutter unit 106 inthe optical axis direction. The cam frame 103 is disposed rotatably withrespect to the first rectilinear frame 102 and integrally movably in theoptical axis direction. The cam frame 103 has a substantiallycylindrical cam frame main body 117 (an example of a cam mechanism) anda substantially annular flange 118 (an example of a flange).

From the stowed state shown in FIGS. 8A and 8B to the initial imagingstate shown in FIGS. 9A and 9B, the cam frame 103 moves in the opticalaxis direction while rotating with respect to the fixed frame 107. Fromthe initial imaging state shown in FIGS. 9A and 9B to the telephoto endshown in FIGS. 10A and 10B, the cam frame 103 rotates without moving inthe optical axis direction, with respect to the fixed frame 107.

The stowed state of the lens barrel 100 can also be expressed as thestate in which the combined length of the fixed frame 107 and the camframe 103 in the optical axis direction is shortest.

As shown in FIG. 5, the flange 118 of the cam frame 103 protrudesoutward from the rear end of the cam frame main body 117.

As shown in FIGS. 11 to 13, the flange 118 has a substantially annularflange main body 151, three cam followers 119A, 119B, and 119C, a gearportion 120, three first bayonet couplers 121, and recesses 150 (anexample of a first insertion portion).

The cam followers 119A, 119B, and 119C extend outward in the radialdirection from the flange main body 151, and have a shape that isslender in the peripheral direction. The cam followers 119A, 119B, and119C are such that the spacing between the cam follower 119A and the camfollower 119B is longer than the spacing between other adjacent camfollowers. Also, the cam followers 119A, 119B, and 119C are disposedunevenly in the peripheral direction, and the cam follower 119A isoffset to the rear (the image plane side) with respect to the camfollowers 119B and 119C (see FIGS. 8 and 25).

The cam follower 119A is inserted into a first cam groove 112A of thefixed frame 107 shown in FIG. 7. The cam follower 119B is inserted intoa first cam groove 112B of the fixed frame 107 shown in FIG. 7. The camfollower 119C is inserted into a first cam groove 112C of the fixedframe 107 shown in FIG. 7. As shown in FIG. 11, the cam follower 119A isoffset to the rear with respect to the cam followers 119B and 119C. Thefirst cam groove 112A is also offset to the rear with respect to thefirst cam grooves 112B and 112C. The cam frame 103 is supported by thefixed frame 107 via the cam followers 119A to 119C.

When the fixed frame 107 and the cam frame 103 rotate relatively, thecam followers 119A to 119C are guided by the first cam grooves 112A to112C, respectively. When this happens, the cam frame 103 moves in theoptical axis direction while rotating with respect to the fixed frame107.

The gear portion 120 shown in FIGS. 11 to 13 meshes with the drive gear114 (see FIG. 6). The cam frame 103 is rotationally driven by the zoommotor unit 116 through the gear portion 120 and the drive gear 114. Asshown in FIG. 13, the gear portion 120 extends in a slender shape in theperipheral direction along the outer peripheral part of the flange mainbody 151.

As shown in FIGS. 11 to 13, the gear portion 120 is disposed atsubstantially the same position as the cam followers 119B and 119C inthe optical axis direction. On the other hand, as shown in FIG. 13, thecam follower 119A is offset to the rear with respect to the camfollowers 119B and 119C. Specifically, the gear portion 120 is offsetfrom the cam follower 119A in the optical axis direction.

As shown in FIGS. 11 to 13, the gear portion 120 has a first end 120Aand a second end 120B. As shown in FIG. 11, the first end 120A isdisposed in front of (on the subject side of) the cam follower 119A. Inother words, the cam follower 119A is disposed to the rear of the firstend 120A (on the image plane side). The first end 120A is integral withthe cam follower 119A, and touches the cam follower 119A. In contrast,the second end 120B is disposed aligned with the cam follower 119B, butwith a space in between in the peripheral direction. The cam follower119B is not integral with the second end 120B.

Also, as shown in FIG. 14, the length E1 of the first end 120A in theoptical axis direction is shorter than the length E2 of the gear portion120 in the optical axis direction in order to shorten the total lengthof the first end 120A and the cam follower 119A in the optical axisdirection. The first end 120A meshes with the drive gear 114 when thelens barrel 100 is in its stowed state. Meanwhile, the second end 120Bmeshes with the drive gear 114 when the lens barrel 100 is at thetelephoto end.

As shown in FIGS. 11 to 13, the three first bayonet couplers 121 aredisposed spaced apart substantially equidistantly in the peripheraldirection of the cam frame main body 117. The first bayonet couplers 121protrude forward from the flange main body 151. The first bayonetcouplers 121 engage with third bayonet couplers 129 (see FIG. 5) of thefirst rectilinear frame 102. The first bayonet couplers 121 are disposedon the outer peripheral side of the cam frame main body 117. A gap isleft between the first bayonet couplers 121 and the cam frame main body117, forming a stowage space S. In other words, the stowage space S isformed by the first bayonet couplers 121 and the cam frame main body117. The end of the first lens frame 101 (see FIG. 5) can be insertedinto the stowage space S.

As shown in FIG. 11, the first bayonet couplers 121 each have a baseplate 121B and a bayonet 121A. The base plates 121B (an example of abase portion) protrude forward from the flange main body 151. The baseplates 121B are flat portions that extend in a slender shape in theperipheral direction of the cam frame 103. The stowage space S is formedbetween the base plates 121B and the cam frame main body 117. Thebayonets 121A (an example of a guide protrusion) protrude outward fromthe base plates 121B in the radial direction of the cam frame main body117. The bayonets 121A extend in a slender shape in the peripheraldirection along the outer peripheral faces of the base plates 121B.

In this embodiment, as shown in FIGS. 11 and 13, the length of thebayonets 121A in the peripheral direction is shorter than the length ofthe base plates 121B in the peripheral direction. The bayonets 121A areinserted into rotary grooves 175 (see FIG. 5) of the third bayonetcouplers 129 provided to the first rectilinear frame 102.

As shown in FIGS. 11 and 12, the flange main body 151 has through-holes121C. More precisely, the flange main body 151 has three through-holes121C. The through-holes 121C are formed between the cam frame main body117 and the base plates 121B. In other words, at least part of the space(an example of a second space) formed by the through-holes 121C (anexample of a second insertion portion) is formed between the cam framemain body 117 and the base plates 121B. More specifically, thethrough-holes 121C are disposed on the inner peripheral side of thefirst bayonet couplers 121. More precisely, the through-holes 121C aredisposed between the first bayonet couplers 121 and the cam frame mainbody 117. The through-holes 121C extend in a slender shape in theperipheral direction. When the lens barrel 100 is in its stowed state,three protrusions 101C of the first lens frame 101 are respectivelyinserted into the three through-holes 121C. The through-holes 121C aredisposed at substantially the same positions as the base plates 121B inthe peripheral direction.

As shown in FIGS. 11 to 13, three front cam grooves 125A, three rear camgrooves 125B, and three second bayonet couplers 126 are formed on theinner face of the cam frame main body 117. The front cam grooves 125Aand the rear cam grooves 125B guide the shutter unit 106. Front cam pins139A of the shutter unit 106 are inserted into the front cam grooves125A. Rear cam pins 139B of the shutter unit 106 are inserted into therear cam grooves 125B. The second bayonet couplers 126 engage with afirst rotary guide 162 and a second rotary guide 163 (discussed below)of the second rectilinear frame 104.

As shown in FIG. 11, the recesses 150 are formed in the flange 118. Moreprecisely, three recesses 150 are formed in the flange 118. The recesses150 are disposed substantially spaced equidistantly in the peripheraldirection of the cam frame 103. The recesses 150 are disposed betweenadjacent first bayonet couplers 121.

The recesses 150 form spaces (an example of a first space) which atleast part of first guide protrusions 136A enter. As to the depth of therecesses 150 in the optical axis direction, the depth of the recesses150 on the outside in the radial direction is less than the depth of therecesses 150 on the inside in the radial direction. The recesses 150gradually become deeper moving from the cam frame main body 117 towardthe outside in the radial direction.

When the first lens frame 101 has moved closest to the flange 118, thethree first guide protrusions 136A (see FIG. 5) formed on the first lensframe 101 go into the three recesses 150. The length of the recesses 150in the peripheral direction is greater than the length of the firstguide protrusions 136A in the peripheral direction.

As shown in FIGS. 11 to 13, the cam frame 103 has three sets of camfollowers 122 and three auxiliary grooves 123. The cam followers 122 andthe auxiliary grooves 123 are formed on the outer peripheral face of thecam frame main body 117.

As shown in FIGS. 11 to 13, the cam followers 122 each have a front campin 122A (an example of a first cam follower or a second cam follower)and a rear cam pin 122B (an example of a first cam follower or a secondcam follower). That is, the three front cam pins 122A and the three rearcam pins 122B are provided to the outer peripheral face of the cam framemain body 117. In this embodiment, the three front cam pins 122A and thethree rear cam pins 122B all have the same shape.

The three sets of cam followers 122 are disposed equidistantly spacedapart in the peripheral direction. The paired front cam pins 122A andrear cam pins 122B are disposed spaced apart in the optical axisdirection. The front cam pins 122A are disposed in front of the rear campins 122B. The positions of the front cam pins 122A and the rear campins 122B in the peripheral direction are the same. Consequently, theshape of the outer periphery of the cam frame 103 can be simplified, andit is easier to produce a mold for the cam pin-shaped parts in injectionmolding.

As shown in FIGS. 14 to 16, the front cam pins 122A are inserted intofront cam grooves 138A (an example of a first guide cam groove or asecond guide cam groove) of the first lens frame 101 (discussed below).The rear cam pins 122B are inserted into rear cam grooves 138B (anexample of a first guide cam groove or a second guide cam groove) of thefirst lens frame 101 (discussed below). The cam followers 122 (122A,122B), the front cam grooves 138A, and the rear cam grooves 138Bconstitute a cam mechanism M1 (an example of a cam mechanism).

The cam mechanism M1 guides the first lens frame 101 in the optical axisdirection. In other words, the cam frame 103 uses the cam mechanism M1to guide the first lens frame 101 in the optical axis direction. Duringoperation in which the first lens frame 101 and the cam frame 103 rotaterelatively, the cam mechanism M1 has a first state, a second state, anda third state. The first state is a state in which the front cam pins122A are guided by the front cam grooves 138A. The second state is astate in which the front cam pins 122A are guided by the front camgrooves 138A, and the rear cam pins 122B are guided by the rear camgrooves 138B. The third state is a state in which the rear cam pins 122Bare guided by the rear cam grooves 138B. In the third state, at leastpart of the front cam pins 122A goes into recesses 101E in a lenssupport 101D. In the first state, the rear cam pins 122B are not guidedby the rear cam grooves 138B. Also, in the third state, the front campins 122A are not guided by the front cam grooves 138A.

With this cam mechanism M1, compared to when just the front cam grooves138A and the front cam pins 122A are provided, the amount of movement ofthe first lens frame 101 in the optical axis direction can be lengthenedby an amount equal to how much the rear cam pins 122B are guided by therear cam grooves 138B in the third state. The front cam pins 122A aredisposed in front of the rear cam pins 122B. The positions of the frontcam pins 122A and the rear cam pins 122B in the peripheral direction arethe same. Consequently, the shape of the outer periphery of the camframe 103 can be simplified, and it is easier to produce a mold for thecam pin-shaped parts in injection molding.

As shown in FIG. 11, the auxiliary grooves 123 in the cam frame 103 areformed so as to trace the path over which reinforcing portions 137(discussed below) move. The path over which the reinforcing portions 137move is indicated in FIGS. 14 and 15 by 137T. More specifically, themovement path 137T of the reinforcing portions 137 is the path traced bythe reinforcing portions 137 when the cam followers 122 of the cam frame103 shown in FIG. 11 move along the second cam grooves 138 (138A, 138B;see FIG. 21) of the first lens frame 101.

As shown in FIG. 11, the auxiliary grooves 123 have a first section 123Aand a second section 123B. The first section 123A and second section123B have bottom faces 124A and 124B, respectively.

As shown in FIG. 11, the first section 123A is a groove formed in theouter peripheral face of the cam frame main body 117. The first section123A is not open at the front. The phrase “the first section 123A is notopen at the front” means that the first section 123A has the bottom face124A and a pair of side faces. In the first section 123A, it can also besaid that there is another wall face constituting a side face, in frontof the bottom face 124A (on the subject side).

Meanwhile, as shown in FIG. 11, the second section 123B is open at thefront. The phrase “the second section 123B is open at the front” meansthat the second section 123B has only one side face (the other sideface) in addition to the bottom face 124B. The second section 123B canbe called a groove, but can also be thought of as a depression orcut-out formed by thinning part of the cam frame main body 117. In thesecond section 123B, it an also be said that there is no other wall facein front of the wall face 124 (on the subject side).

The second section 123B is formed by a thin-wall part 182 that isthinner than the surrounding part. The thickness of the thin-wall part182 is less than the standard thickness of the cam frame main body 117.Accordingly, cut-out spaces V formed by the thin-wall part 182 and thesurrounding part along the bottom face 124B are formed at three placeson the outer peripheral part of the cam frame main body 117. When thefirst lens frame 101 and the cam frame 103 rotate relatively, fixingportions 172 of a barrier unit 134 (discussed below) goes into thesecut-out spaces V. Just as with the second section 123B, the firstsection 123A may be open at the front.

(3) First Rectilinear Frame 102

As shown in FIG. 5, the first rectilinear frame 102 is provided torestrict the rotation of the first lens frame 101 with respect to thefixed frame 107. The first rectilinear frame 102 is supported by thefixed frame 107. The first rectilinear frame 102 has a substantiallycylindrical main body part 102A and six rectilinear guide projections127. The rectilinear guide projections 127 protrude outward in theradial direction from the outer face of the body part 102A.

The first rectilinear frame 102 will now be described in detail. Therectilinear guide projections 127 are inserted into the rectilinearguide grooves 113 (see FIG. 7) of the fixed frame 107. The rectilinearguide projections 127 are guided in the optical axis direction by therectilinear guide grooves 113. The first rectilinear frame 102 issupported by the fixed frame 107 via the rectilinear guide projections127 and the rectilinear guide grooves 113. The rectilinear guideprojections 127 and the rectilinear guide grooves 113 allow the firstrectilinear frame 102 to move in the optical axis direction with respectto the fixed frame 107, and restrict the rotation of the firstrectilinear frame 102 with respect to the fixed frame 107.

As shown in FIG. 5, six rectilinear guide grooves 128 (an example of arectilinear groove) and the third bayonet couplers 129 are formed on theinner face of the first rectilinear frame 102. The rectilinear guidegrooves 128 extend in the optical axis direction. The third bayonetcouplers 129 have the rotary grooves 175 that extend in the peripheraldirection.

The third bayonet couplers 129 engage with the first bayonet couplers121 of the cam frame 103 (see FIG. 11). Since the third bayonet couplers129 and the first bayonet couplers 121 are engaged, the firstrectilinear frame 102 moves integrally with the cam frame 103 in theoptical axis direction, and the cam frame 103 is able to rotate withrespect to the first rectilinear frame 102.

(4) Second Rectilinear Frame 104

The second rectilinear frame 104 is provided to restrict the rotation ofthe shutter unit 106 with respect to the fixed frame 107. As shown inFIG. 5, the second rectilinear frame 104 has a first guide plate 131A(an example of a rectilinear guide), a second guide plate 131B (anexample of a rectilinear guide), three projections 132, the first rotaryguide 162, and the second rotary guide 163.

The second rectilinear frame 104 will now be described in detail. Asshown in FIG. 17, the an annular portion 130 has a disk portion 165 andan inner peripheral protrusion 161 (an example of a rib). The innerperipheral protrusion 161 protrudes in the optical axis direction fromthe inner peripheral part of the disk portion 165. The inner peripheralprotrusion 161 is a substantially annular portion, and is formed alongthe inner peripheral part of the disk portion 165.

As shown in FIG. 17, the first guide plate 131A and the second guideplate 131B extend forward from the inner peripheral part of the annularportion 130, and are disposed substantially equidistantly spaced in theperipheral direction. More precisely, the first guide plate 131A and thesecond guide plate 131B extend forward from the inner peripheral face ofthe inner peripheral protrusion 161 of the annular portion 130. Thefirst guide plate 131A and the second guide plate 131B are respectivelyinserted into rectilinear guide grooves 140 (see FIG. 6) of the shutterunit 106 (discussed below).

The projections 132 protrude outward in the radial direction from theouter peripheral part of the annular portion 130. The three projections132 are respectively inserted into the three rectilinear guide grooves113 of the fixed frame 107 (see FIG. 7). The second rectilinear frame104 is supported by the fixed frame 107 via the projections 132 and therectilinear guide grooves 113. Since the projections 132 are insertedinto the rectilinear guide grooves 113, the second rectilinear frame 104is able to move in the optical axis direction with respect to the fixedframe 107, and its rotation is restricted with respect to the fixedframe 107.

As shown in FIG. 17, the first rotary guide 162 is disposed at the baseof the first guide plate 131A. The first rotary guide 162 extends in aslender shape in the peripheral direction.

As shown in FIG. 18, the length of the first rotary guide 162 in theperipheral direction is greater than the length of the first guide plate131A in the peripheral direction. The first guide plate 131A is disposedwithin the range in the peripheral direction over which the first rotaryguide 162 is formed. As shown in FIG. 19A, a first region B1 of theannular portion 130 occupied by the first guide plate 131A in theperipheral direction is disposed on the inside of a second region B 11of the annular portion 130 occupied by the first rotary guide 162 in theperipheral direction. When the second rectilinear frame 104 is viewed inthe radial direction, it can also be said that the first rotary guide162 protrudes on both sides of the first guide plate 131A.

As shown in FIG. 17, the first rotary guide 162 has a first bayonet 162Aand a second bayonet 162B. The first bayonet 162A and the second bayonet162B protrude outward in the radial direction from the outer peripheralface of the inner peripheral protrusion 161 of the annular portion 130.The first bayonet 162A and the second bayonet 162B extend in a slendershape in the peripheral direction along the outer peripheral face of theinner peripheral protrusion 161. The first bayonet 162A and the secondbayonet 162B are inserted into rotary guide grooves 166 of the secondbayonet couplers 126 of the cam frame 103 (see FIGS. 11 to 13).

As shown in FIG. 17, a slit 162C is formed in the peripheral directionbetween the first bayonet 162A and the second bayonet 162B. The firstrotary guide 162 can also be said to be divided in two in the peripheraldirection by the slit 162C. The slit 162C is disposed around the base ofthe first guide plate 131A.

Also, as shown in FIG. 18, the length of the slit 162C in the peripheraldirection is less than the length of the first guide plate 131A in theperipheral direction. As shown in FIG. 19A, the end of the first bayonet162A and/or the second bayonet 162B is disposed in a first region B2occupied by the second guide plate 131B.

As shown in FIG. 17, the second rotary guide 163 is disposed at the baseof the second guide plate 131B. The second rotary guide 163 extends in aslender shape in the peripheral direction.

As shown in FIG. 18, the length of the second rotary guide 163 in theperipheral direction is greater than the length of the second guideplate 131B in the peripheral direction. The second guide plate 131B isdisposed within the range in the peripheral direction over which thesecond rotary guide 163 is formed. As shown in FIG. 19B, in theperipheral direction of the annular portion 130, the first region B2occupied by the second guide plate 131B is disposed on the inside of asecond region B 12 of the annular portion 130 occupied by the secondrotary guide 163 in the peripheral direction. When the secondrectilinear frame 104 is viewed in the radial direction, it can also besaid that the second rotary guide 163 protrudes on both sides of thesecond guide plate 131B.

As shown in FIGS. 17 and 18, the second rotary guide 163 has a firstbayonet 163A and a second bayonet 163B. The first bayonet 163A and thesecond bayonet 163B protrude outward in the radial direction from theouter peripheral face of the inner peripheral protrusion 161 of theannular portion 130. The first bayonet 163A and the second bayonet 163Bextend in a slender shape in the peripheral direction along the outerperipheral face of the inner peripheral protrusion 161. The firstbayonet 163A and the second bayonet 163B are inserted into the rotaryguide grooves 166 of the second bayonet couplers 126 of the cam frame103 (see FIGS. 11 to 13).

As shown in FIGS. 17 and 18, a slit 163C is formed in the peripheraldirection between the first bayonet 163A and the second bayonet 163B. Itcan also be said that the second rotary guide 163 is divided in two inthe peripheral direction by the slit 163C. As shown in FIGS. 18 and 19B,the slit 163C is disposed near the range in the peripheral directionover which the second guide plate 131B is formed.

(5) First Lens Frame 101

As shown in FIGS. 4 to 6 and FIGS. 8 to 10, the first lens frame 101supports the first lens group G1. The first lens frame 101 is disposedso as to be able to rotate in the optical axis direction withoutrotating with respect to the fixed frame 107. As shown in FIG. 20, thefirst lens frame 101 has a main body portion 101A, the three first guideprotrusions 136A (an example of rectilinear projections) the threeprotrusions 101C, the three reinforcing portions 137, and the lenssupport 101D that supports the first lens group G1.

As shown in FIGS. 8 to 10, the first lens group G1 is supported by themain body portion 101A.

The first lens frame 101 will now be described in detail. As shown inFIG. 20, the second cam grooves 138 are formed in the inner peripheralface of the main body portion 101A. As shown in FIGS. 14 to 16, thesecond cam grooves 138 have the three front cam grooves 138A and thethree rear cam grooves 138B. The front cam pins 122A of the cam frame103 are inserted into the front cam grooves 138A. The rear cam pins 122Bof the cam frame 103 are inserted into the rear cam grooves 138B.

As shown in FIG. 20, the three protrusions 101C are disposedsubstantially equidistantly spaced in the peripheral direction of thefirst lens frame 101. The three protrusions 101C protrude rearward fromthe end of the main body portion 101A. In the stowed state of the lensbarrel 100, the entire end (all the way around) of the first lens frame101 is accommodated in the stowage space S. In the stowed state of thelens barrel 100, the protrusions 101C are inserted into theabove-mentioned through-holes 121C of the cam frame 103.

As shown in FIG. 20, the three first guide protrusions 136A and threesecond guide protrusions 136B are disposed at the rear end of the mainbody portion 101A. The three first guide protrusions 136A and threesecond guide protrusions 136B protrude outward in the radial directionfrom the main body portion 101A. The first guide protrusions 136A andthe second guide protrusions 136B are respectively inserted into the sixrectilinear guide grooves 128 of the first rectilinear frame 102 (seeFIGS. 5, 9, and 10). The three first guide protrusions 136A are disposedsubstantially equidistantly spaced in the peripheral direction. Thelength of the distal ends of the first guide protrusions 136A in theoptical axis direction is greater than the length of the bases of thefirst guide protrusions 136A in the optical axis direction. The lengthof the first guide protrusions 136A in the optical axis directiongradually decreases toward the outside in the radial direction of thefirst lens frame 101. The distal ends of the first guide protrusions136A protrude more toward the flange 118 side than the bases of thefirst guide protrusions 136A. The three second guide protrusions 136Bare disposed substantially equidistantly spaced in the peripheraldirection.

As shown in FIGS. 8, 9, 10, 20, and 21, the second guide protrusions136B are plate-shaped portions. In contrast, the first guide protrusions136A have a special shape. More specifically, the distal ends of thefirst guide protrusions 136A are thicker than the bases. The length ofthe first guide protrusions 136A in the optical axis direction graduallyincreases outward in the radial direction. The length of the distal endsof the first guide protrusions 136A in the optical axis direction isgreater than the length of the second guide protrusions 136B in theoptical axis direction. Also, the length of the distal ends of the firstguide protrusions 136A in the optical axis direction is greater than theoptical axis direction width of the third bayonet couplers 129 of thefirst rectilinear frame 102 (see FIG. 5). The distal ends of the firstguide protrusions 136A protrude rearward more than the bases.

The first guide protrusions 136A and the second guide protrusions 136Bengage with the rectilinear guide grooves 128, and as a result the firstlens frame 101 is supported by the first rectilinear frame 102. Thefirst lens frame 101 is able to move in the optical axis direction withrespect to the first rectilinear frame 102, but its rotation isrestricted with respect to the first rectilinear frame 102.

The lens support 101D has recesses 101E that are recessed in the opticalaxis direction. Here, an example is given in which the lens support 101Dhas the recesses 101E, but the recesses 101E may be replaced by holesthat pass through in the optical axis direction.

As shown in FIGS. 2 and 3, the barrier unit 134 (an example of a barriermechanism) is attached to the front side of the main body portion 101A.As shown in FIG. 5, the barrier unit 134 has a pair of barrier vanes135, a barrier case 173, and three mounting portions 134A.

The barrier vanes 135 are provided openably and closeably to the barriercase 173. The barrier case 173 supports the barrier vanes 135. Thebarrier case 173 has an opening 173A (see FIGS. 2 and 3). In the stowedstate of the lens barrel 100, the opening 173A is closed by the barriervanes 135. Consequently, the barrier vanes 135 protect the first lensgroup G1 and block light from entering the optical system O (see FIG.2). During imaging, the barrier vanes 135 are opened, and light isguided through the opening 173A to the optical system O (see FIG. 3).

As shown in FIG. 5, the three mounting portions 134A protrude in theoptical axis direction from the barrier case 173. The three mountingportions 134A form part of the fixing portions 172. The three mountingportions 134A are disposed substantially equidistantly spaced in theperipheral direction. As shown in FIG. 21, the three mounting portions134A have attachment holes 134B. Projections 101B of the first lensframe 101 are fitted into the attachment holes 134B, or the mountingportions 134A are hooked onto the projections 101B. Consequently, thebarrier unit 134 is mounted to the first lens frame 101 via the mountingportions 134A and the projections 101B. Here, the mounting portions 134Aand the projections 101B are called the fixing portions 172 of thebarrier unit 134 and the first lens frame 101.

As discussed above, three cut-out spaces V are formed in the outerperipheral part of the cam frame 103. As shown in FIGS. 22A and 23A,when the lens barrel 100 is in its stowed state (retracted), part of thefixing portions 172 composed of the mounting portions 134A and theprojections 101B goes into the cut-out spaces V. Meanwhile, as shown inFIGS. 22B and 23B, when the lens barrel 100 is deployed, the fixingportions 172 move away from the cut-out spaces V.

As shown in FIG. 21, the three reinforcing portions 137 protrude inwardin the radial direction from the inner peripheral face of the main bodyportion 101A. The reinforcing portions 137 are inserted into theauxiliary grooves 123 of the cam frame 103 (see FIG. 11).

The reinforcing portions 137 basically do not touch the face in whichthe auxiliary grooves 123 are formed. Specifically, a tiny gap is formedbetween the reinforcing portions 137 and the cam frame 103. For example,if an external force is exerted on the lens barrel 100, and the variousframes are deformed, some of the external force can be dispersed byhaving the reinforcing portions 137 come into contact with the sidewalls of the auxiliary grooves 123. Therefore, there will be less damageto the cam followers, such as the front cam pins 122A and the rear campins 122B. The configuration may also be such that the reinforcingportions 137 are in contact with the auxiliary grooves 123 from theoutset.

(6) Second Lens Frame 105

As shown in FIG. 6, the second lens frame 105 supports the second lensgroup G2. The second lens frame 105 is movably supported by the shutterunit 106. More specifically, the second lens frame 105 is disposedmovably within a plane perpendicular to the optical axis AX, withrespect to the shutter unit 106. Movement of the second lens frame 105in the optical axis direction with respect to the shutter unit 106 isrestricted. The position of an optical image on the light receiving faceof the CCD image sensor 110 can be varied by moving the second lensframe 105 within a plane perpendicular to the optical axis AX, withrespect to the shutter unit 106. For example, the second lens frame 105is driven so as to suppress blurring of the optical image caused byshaking of the digital camera 1. The drive of the second lens frame 105with respect to the shutter unit 106 is performed by a drive unit (notshown).

(7) Shutter Unit 106

As shown in FIG. 6, the shutter unit 106 is provided to adjust theamount of light that reaches the CCD image sensor 110. The shutter unit106 adjusts the timing at which the shutter vanes are opened and closedaccording to the preset shutter speed. When the shutter unit 106 isopen, light that has passed through the opening in the shutter unit 106reaches the CCD image sensor 110. On the other hand, when the shutterunit 106 is closed, the shutter unit 106 blocks light.

The shutter unit 106 has a shutter main body 106A, three sets of camfollowers 139 (139A and 139B in FIG. 6), and the two rectilinear guidegrooves 140. The three sets of cam followers 139 and the two rectilinearguide grooves 140 are formed on the outer peripheral face of the shuttermain body 106A.

As shown in FIG. 6, the cam followers 139 have the front cam pins 139Aand the rear cam pins 139B. More specifically, the three front cam pins139A and the three rear cam pins 139B are provided to the outerperipheral face of the shutter main body 106A. The three front cam pins139A all have the same shape. The three rear cam pins 139B all have thesame shape. The three sets of cam followers 139 are disposedequidistantly spaced in the peripheral direction. The paired front campins 139A and rear cam pins 139B are disposed spaced apart in theoptical axis direction. The front cam pins 139A are disposed in front ofthe rear cam pins 139B. The positions of the front cam pins 139A in theperipheral direction are offset from the positions of the rear cam pins139B in the peripheral direction.

As shown in FIGS. 9A, 9A, and 10A and FIGS. 11 to 13, the front cam pins139A are inserted into the front cam grooves 125A of the cam frame 103.As shown in FIG. 10A, the rear cam pins 139B are inserted into the rearcam grooves 125B of the cam frame 103. The shutter unit 106 is supportedby the cam frame 103 via the cam followers 139, the front cam grooves125A, and the rear cam grooves 125B. The cam followers 139, the frontcam grooves 125A, and the rear cam grooves 125B constitute a cammechanism M2 (an example of a cam mechanism).

The cam mechanism M2 guides the shutter unit 106 in the optical axisdirection. In other words, the cam frame 103 uses the cam mechanism M2to guide the shutter unit 106 in the optical axis direction. Duringoperation in which the shutter unit 106 and the cam frame 103 rotaterelatively, the cam mechanism M2 has a first state, a second state, anda third state. The first state is a state in which the front cam pins139A are guided by the front cam grooves 125A. The second state is astate in which the front cam pins 139A are guided by the front camgrooves 125A, and the rear cam pins 139B are guided by the rear camgrooves 125B. The third state is a state in which the rear cam pins 139Bare guided by the rear cam grooves 125B. In the first state, the rearcam pins 139B are not guided by the rear cam grooves 125B. And in thethird state, the front cam pins 139A are not guided by the front camgrooves 125A.

With this cam mechanism M2, compared to when just the front cam grooves125A and the front cam pins 139A are provided, the amount of movement ofthe shutter unit 106 in the optical axis direction can be lengthened byan amount equal to how much the rear cam pins 139B are guided by therear cam grooves 125B in the third state.

The first guide plate 131A and the second guide plate 131B of the secondrectilinear frame 104 are respectively inserted into the rectilinearguide grooves 140. Therefore, the shutter unit 106 is able to move inthe optical axis direction with respect to the second rectilinear frame104, but its rotation is restricted with respect to the secondrectilinear frame 104.

(8) Third Lens Frame 108

As shown in FIG. 6, the third lens frame 108 supports the third lensgroup G3. The third lens frame 108 has a rectilinear guide 141, ananti-rotation portion 142, and a nut engagement portion 143. A firstguide pole 144 is inserted into the rectilinear guide 141. The firstguide pole 144 is fixed to the master flange 109. The first guide pole144 extends forward from the master flange 109. The third lens frame 108is supported movably in the optical axis direction by the rectilinearguide 141 and the first guide pole 144 with respect to the master flange109. A second guide pole 145 is inserted into the anti-rotation portion142. The second guide pole 145 is fixed to the master flange 109. Thesecond guide pole 145 extends forward from the master flange 109.Rotation of the third lens frame 108 around the first guide pole 144 isrestricted by the anti-rotation portion 142 and the second guide pole145. A nut 149 of a focus motor unit 148 is engaged with the nutengagement portion 143.

The third lens frame 108 is driven in the optical axis direction withrespect to the master flange 109 by the focus motor unit 148. The focusmotor unit 148 has a motor 148A and a lead screw 148B that is rotated bythe motor 148A. The motor 148A is fixed to the master flange 109. Thelead screw 148B extends rearward from the motor 148A. The lead screw isthreaded into the nut 149. The rotation of the nut 149 is restricted bythe nut engagement portion 143. Therefore, when the lead screw rotates,the nut 149 is driven in the optical axis direction, and the nutengagement portion 143 is driven in the optical axis direction by thenut 149. That is, the third lens frame 108 is driven in the optical axisdirection with respect to the fixed frame 107 by the focus motor unit148.

(9) Master Flange 109

As shown in FIG. 6, the first guide pole 144 and the second guide pole145 are fixed to the master flange 109. The master flange 109 supportsthe third lens frame 108 movably in the optical axis direction via thefirst guide pole 144 and the second guide pole 145.

A CCD attachment plate 146 is also fixed to the master flange 109. TheCCD image sensor 110 is sandwiched between the master flange 109 and theCCD attachment plate 146. Light that has passed through an opening 147in the master flange 109 arrives the light receiving face of the CCDimage sensor 110.

A depression 109A is formed in the front face of the master flange 109in order to prevent the cam follower 119A of the cam frame 103 frominterfering with the master flange 109. In the stowed state of the lensbarrel 100, the cam follower 119A of the cam frame 103 goes into thedepression 109A. This prevents the lens barrel 100 from becoming largerin the optical axis direction even though the cam follower 119A isdisposed more to the rear than the cam followers 119B and 119C.

<Operation of Lens Barrel>

Next, the operation of the lens barrel 100 will be described.

When a power switch 10 is turned on, the lens barrel 100 is driven fromits stowed state (FIGS. 8A and 8B) to the initial imaging state (FIGS.9A and 9B). More specifically, when the drive gear 114 is rotationallydriven by the zoom motor unit 116, the cam frame 103 rotates in an R1direction with respect to the fixed frame 107 via the gear portion 120.In this embodiment, the initial imaging state corresponds to a state inwhich the lens barrel 100 is located at the wide angle end.

When the lens barrel 100 is in its stowed state, the drive gear 114meshes with the first end 120A of the gear portion 120 (see FIG. 11).When the drive gear 114 is rotationally driven by the zoom motor unit116 in the stowed state of the lens barrel 100, the position at whichthe drive gear 114 meshes with the gear portion 120 changes from thefirst end 120A toward the second end 120B (see FIG. 11).

When the cam frame 103 rotates in the R1 direction (see FIG. 4) withrespect to the fixed frame 107, as shown in FIGS. 8 and 9, the camfollowers of the cam frame 103 (119A to 119C in FIG. 12) are guided bythe first cam grooves 112 of the fixed frame 107 (112A to 112C in FIG.7). First, the cam frame 103 rotates by a specific amount without beingdeployed with respect to the fixed frame 107. Then, the cam frame 103begins to be deployed forward from the fixed frame 107 while rotating.At this point, the first end 120A of the gear portion 120 is disposed onthe front side of the cam follower 119A (see FIG. 11). However,immediately after the start of drive from the stowed state, the camframe 103 rotates without being deployed with respect to the fixed frame107, so the drive gear 114 does not interfere with the cam follower119A.

Meanwhile, as shown in FIGS. 8 to 10, the third bayonet couplers 129 ofthe first rectilinear frame 102 engage with the first bayonet couplers121 of the cam frame 103. Accordingly, when the cam frame 103 isdeployed in the optical axis direction while rotating with respect tothe fixed frame 107, the first rectilinear frame 102 moves integrallywith the cam frame 103 in the optical axis direction. At this point, therectilinear guide projections 127 of the first rectilinear frame 102 areguided in the optical axis direction by the rectilinear guide grooves113 of the fixed frame 107, so the first rectilinear frame 102 does notrotate with respect to the fixed frame 107.

When the cam frame 103 rotates in the R1 direction (see FIG. 4) withrespect to the fixed frame 107, as shown in FIG. 9A, the front cam pins122A moves through the front cam grooves 138A of the first lens frame101. Also, as shown in FIGS. 8, 9A, 10A, and 14 to 16, the rear cam pins122B move through the rear cam grooves 138B of the first lens frame 101.

At this point, as shown in FIG. 9, the first guide protrusions 136A andthe second guide protrusions 136B of the first lens frame 101 (see FIG.20) are guided in the optical axis direction by the rectilinear guidegrooves 128 of the first rectilinear frame 102. Specifically, therotation of the first lens frame 101 with respect to the fixed frame 107is restricted by the first rectilinear frame 102.

Therefore, when the cam frame 103 rotates in the R1 direction withrespect to the fixed frame 107 (see FIG. 4), the first lens frame 101moves in the optical axis direction with respect to the cam frame 103,according to the shape of the front cam grooves 138A and the rear camgrooves 138B, without rotating with respect to the first rectilinearframe 102 or the fixed frame 107. Thus, when the cam frame 103 and thefirst lens frame 101 rotate relatively, the movement path 137T of thereinforcing portions 137, the movement path 122AT of the front cam pins122A, and the movement path 122BT of the rear cam pins 122B are as shownin FIGS. 14 to 16.

Furthermore, as shown in FIGS. 9B and 17 to 19, the first rotary guide162 and second rotary guide 163 of the second rectilinear frame 104engage with the second bayonet couplers 126 of the cam frame 103.Accordingly, when the cam frame 103 is deployed in the optical axisdirection while rotating with respect to the fixed frame 107, the secondrectilinear frame 104 moves integrally with the cam frame 103 in theoptical axis direction. At this point the projections 132 of the secondrectilinear frame 104 are guided in the optical axis direction by therectilinear guide grooves 113 of the fixed frame 107. Specifically, thesecond rectilinear frame 104 does not rotate with respect to the fixedframe 107.

As shown in FIG. 9B, the first guide plate 131A (see FIG. 5) and secondguide plate 131B of the second rectilinear frame 104 are inserted intothe rectilinear guide grooves 140 of the shutter unit 106. Consequently,the shutter unit 106 moves in the optical axis direction withoutrotating with respect to the fixed frame 107.

As shown in FIGS. 8A to 10A, the front cam pins 139A and rear cam pins139B of the shutter unit 106 are inserted into the front cam grooves125A and rear cam grooves 125B of the cam frame 103. Specifically, theshutter unit 106 is supported by the cam frame 103 via the cam mechanismM2 (the front cam grooves 125A and the rear cam grooves 125B).Therefore, when the cam frame 103 rotates with respect to the fixedframe 107, the shutter unit 106 moves in the optical axis direction withrespect to the cam frame 103 according to the shape of the front camgrooves 125A and the rear cam grooves 125B.

The third lens frame 108 is driven in the optical axis direction withrespect to the master flange 109 by the focus motor unit 148.

Drive by the zoom motor unit 116 stops when the rotational angle of thecam frame 103 with respect to the fixed frame 107 reaches a specificangle. Then, the lens barrel 100 stops in the initial imaging stateshown in FIGS. 9A and 9B.

<Features of Lens Barrel>

Features of the lens barrel 100 described above are compiled below.

(1-1)

As shown in FIG. 7, the fixed frame 107 (first frame) has the first camgrooves 112A to 112C. As discussed above, the drive gear 114 is disposedrotatably with respect to the fixed frame 107. As shown in FIG. 12, thedrive gear 114 is disposed rotatably with respect to the fixed frame107. As shown in FIG. 12, the cam frame 103 (second frame) has theplurality of cam followers 119A to 119C and the gear portion 120 thatmeshes with the drive gear 114. The cam follower 119A is inserted intothe first cam groove 112A. The cam follower 119B is inserted into thefirst cam groove 112B. The cam follower 119C is inserted into the firstcam groove 112C. Consequently, the cam frame 103 is deployed forward (tothe subject side) from the fixed frame 107 while being rotated by therotation of the drive gear 114. The cam follower 119A is disposed to therear of the first end 120A of the gear portion 120 (on the image planeside, using the gear portion 120 as a reference).

Thus, with this lens barrel 100, since the cam follower 119A is disposedto the rear of the gear portion 120 of the cam frame 103, the gearportion 120 can be lengthened in the peripheral direction withoutincreasing the peripheral direction spacing of the cam followers 119.Therefore, when the drive gear 114 is used to rotationally drive the camframe 103 with respect to the fixed frame 107, the relative rotationalangles of the fixed frame 107 and the cam frame 103 can be increasedwithout sacrificing the support accuracy of the cam frame 103 withrespect to the fixed frame 107.

Also, this increase in the relative rotational angle affords much moremovement of the cam frame 103 with respect to the fixed frame 107 whenthe cam frame 103 is deployed forward from the fixed frame 107 using thecam followers 119A to 119C and the first cam grooves 112A to 112C. Thatis, with this lens barrel 100, a higher zoom ratio can be achievedwithout making the product bulkier.

(1-2)

As shown in FIG. 11, the cam follower 119A of the cam frame 103 isoffset to the rear (the image plane side) with respect to the camfollower 119B and the cam follower 119A. Therefore, the shape of thegear portion 120 can be substantially straight along the peripheraldirection of the cam frame 103.

(1-3)

As shown in FIGS. 11 to 13, the length of the cam follower 119A in theperipheral direction is greater than the length of the cam follower 119Ain the optical axis direction, and this increases the strength of thecam follower 119A. Also, the length of the cam follower 119B in theperipheral direction is greater than the length of the cam follower 119Bin the optical axis direction, and the length of the cam follower 119Cin the peripheral direction is greater than the length of the camfollower 119C in the optical axis direction. Therefore, the strength ofthe cam followers 119B and 119C can also be increased.

If the length of the cam followers 119A to 119C is extended in theperipheral direction, there will be less space between the cam followers119A to 119C. Therefore, if the gear portion 120 is disposed between thecam followers 119A and 119B, it will be difficult to ensure adequatelength of the gear portion 120.

However, with the lens barrel 100, since the cam follower 119A isdisposed to the rear of the first end 120A of the gear portion 120,sufficient length of the gear portion 120 can be ensured in theperipheral direction even though the cam followers 119A to 119C areformed in a long, slender shape in the peripheral direction.

Specifically, employing the above-mentioned configuration allows theimpact resistance of the lens barrel 100 to be increased and the zoomratio to be raised.

(1-4)

As shown in FIG. 14, the length E 1 of the first end 120A of the gearportion 120 in the optical axis direction is less than the maximumlength E2 of the gear portion 120 in the optical axis direction.Consequently, even though the cam follower 119A is disposed to the rearof the first end 120A of the gear portion 120, this helps prevent thelens barrel 100 from becoming bulkier in the optical axis direction.

(1-5)

As shown in FIGS. 11 to 13, the cam follower 119A is in contact with thegear portion 120. More specifically, the cam follower 119A is integralwith the first end 120A of the gear portion 120, and there is no gapbetween the first end 120A and the cam follower 119A. Consequently, thecam follower 119A and the gear portion 120 can increase each other'sstrength, and damage to both can be effectively prevented.

(2-1)

As shown in FIGS. 11 to 13, the stowage space S is formed between thecam frame main body 117 and the first bayonet couplers 121. Accordingly,when the first lens frame 101 moves in the optical axis direction withrespect to the cam frame 103, the entire end of the first lens frame 101(all the way around) can fit in the stowage space S (see FIG. 8A, forexample). Accordingly, the combined length of the cam frame 103 and thefirst lens frame 101 in the optical axis direction can be shorter, andthe lens barrel 100 can be made more compact in the optical axisdirection.

(2-2)

When the combined length of the cam frame 103 and the first rectilinearframe 102 in the optical axis direction is shortest (that is, in thestowed state of the lens barrel 100), the entire end of the first lensframe 101 (all the way around) can fit in the stowage space S. Thisaffords a further reduction in the combined length of the first lensframe 101 and the cam frame 103 in the optical axis direction, andallows the lens barrel 100 to be made even more compact in the opticalaxis direction.

(2-3)

As shown in FIGS. 11 to 13, the first bayonet couplers 121 of the camframe 103 protrude integrally in the optical axis direction from theflange 118 on the outside in the radial direction and near thethrough-holes 121C of the cam frame 103. Accordingly, the first bayonetcouplers 121 increase the strength of the flange 118, and increase theoverall strength of the cam frame 103.

(2-4)

As shown in FIGS. 11 to 13, the flange 118 has the through-holes 121Cdisposed on the inner peripheral side of the first bayonet couplers 121.In the stowed state of the lens barrel 100 shown in FIG. 8A, theprotrusions 101C of the first lens frame 101 are inserted into thethrough-holes 121C. This allows the first lens frame 101 and the camframe 103 to be shorter in length in the optical axis direction, andallows the lens barrel 100 to be more compact in the optical axisdirection.

(3-1)

As shown in FIGS. 8A, 8B, and 11, the flange 118 of the cam frame 103has the recesses 150. When the first lens frame 101 is at its closest tothe flange 118, the first guide protrusions 136A of the first lens frame101 go into the recesses 150. Accordingly, the dimensions of the entirelens barrel 100 can be reduced when the first lens frame 101 is at itsclosest to the flange 118. Therefore, a more compact size in the opticalaxis direction can be achieved with this lens barrel 100.

(3-2)

As shown in FIG. 21, with the first lens frame 101, the length of thedistal ends of the first guide protrusions 136A in the optical axisdirection is greater than the length of the bases of the first guideprotrusions 136A in the optical axis direction. Consequently, even ifthe rectilinear guide grooves 128 of the first rectilinear frame 102 areinterrupted midway by the rotary grooves 1757 of the first rectilinearframe 102, since the length of the distal ends of the first guideprotrusions 136A in the optical axis direction is greater than the widthof the rotary grooves 175 of the first rectilinear frame 102, the distalends of the first guide protrusions 136A can be moved stably within therectilinear guide grooves 128. Therefore, even though a combination ofcam grooves, rotary grooves, and so forth is provided to the rectilinearguide grooves 128, the first guide protrusions 136A can still be guidedstably in the rectilinear guide grooves 128. Specifically, thisincreases latitude in the design of the first rectilinear frame 102.

(3-3)

As shown in FIG. 21, the length of the first guide protrusions 136A inthe optical axis direction gradually increases outward in the radialdirection of the main body portion 101A. The distal ends of the firstguide protrusions 136A protrude in the direction of the flange 118 ofthe cam frame 103, using the bases of the first guide protrusions 136Aas a reference.

If we take into account an overall reduction in the size of the lensbarrel 100 in the optical axis direction, it is preferable for theposition of the first guide protrusions 136A to be farther away from thesubject. This is because the closer the first guide protrusions 136A isdisposed on the subject side, the less the first lens frame 101 can bedeployed with respect to the first rectilinear frame 102.

With this lens barrel 100, since the distal ends of the first guideprotrusions 136A protrude more toward the flange 118 than the bases do,the first guide protrusions 136A can be entirely disposed at positionsfarther away from the subject. Also, when the first guide protrusions136A have moved closer to the flange 118, they will fit in the recesses150 of the cam frame 103. Therefore, the lens barrel 100 can be madeeven more compact.

(3-4)

As shown in FIG. 11, since the recesses 150 of the cam frame 103 areportions recessed in the optical axis direction, the flange 118 will bestronger than when through-holes are provided to the flange 118.Therefore, the lens barrel 100 will also be stronger. If there are noparticular concerns about strength, then the recesses 150 may bethrough-holes (holes) instead. If the recesses 150 are through-holes,the first guide protrusions 136A can be designed to be larger in theoptical axis direction. Therefore, this affords greater latitude in thedesign of the lens barrel 100.

(4-1)

As shown in FIG. 17, with this lens barrel 100, the area around the baseof the first guide plate 131A of the second rectilinear frame 104 isreinforced by the first rotary guide 162. More specifically, as shown inFIGS. 18 and 19A, the first region B1 of the first guide plate 131A isdisposed on the inside of the second region B 11 of the first rotaryguide 162. The first rotary guide 162 protrudes on both sides of theannular portion 130 in the peripheral direction past the first guideplate 131A.

In this case, since the first rotary guide 162 functions as a rib, thestrength around the base of the first guide plate 131A is increased bythe first rotary guide 162.

Furthermore, in a state in which the first rotary guide 162 is insertedinto the rotary guide grooves 166 of the second bayonet couplers 126 ofthe cam frame 103, the first rotary guide 162 is reinforced by the camframe 103. Consequently, the strength around the base of the first guideplate 131A is increased not only by the first rotary guide 162, but alsoby the cam frame 103.

Therefore, when the shutter unit 106 is guided by the cam frame 103 inthe optical axis direction, for example, the area around the base of thefirst guide plate 131A will be less likely to be damaged if a force inthe peripheral direction should be exerted on the first guide plate131A.

Similarly, the area around the base of the second guide plate 131B ofthe second rectilinear frame 104 is reinforced by the second rotaryguide 163. More specifically, as shown in FIGS. 18 and 19B, the firstregion B2 of the second guide plate 131B is disposed on the inside ofthe second region B12 of the second rotary guide 163. The second rotaryguide 163 protrudes on both sides of the annular portion 130 in theperipheral direction past the second guide plate 131B.

In this case, since the second rotary guide 163 functions as a rib, thestrength of the area around the base of the second guide plate 131B isincreased by the second rotary guide 163.

Furthermore, in a state in which the second rotary guide 163 (see FIG.17) is inserted into the rotary guide grooves 166 (see FIG. 11) of thesecond bayonet couplers 126 of the cam frame 103, the second rotaryguide 163 is reinforced by the cam frame 103. Consequently, the strengtharound the base of the second guide plate 131B is increased not only bythe second rotary guide 163, but also by the cam frame 103.

Therefore, when the shutter unit 106 is guided by the cam frame 103 inthe optical axis direction, for example, the area around the base of thesecond guide plate 131B will be less likely to be damaged if a force inthe peripheral direction should be exerted on the second guide plate131B.

(4-2)

As shown in FIG. 17, the annular portion 130 has the inner peripheralprotrusion 161. This inner peripheral protrusion 161 increases thestrength of the annular portion 130. Furthermore, the first rotary guide162 has the first bayonet 162A an the second bayonet 162B. The firstbayonet 162A an the second bayonet 162B protrude outward in the radialdirection from the inner peripheral protrusion 161. This increases thestrength of the inner peripheral protrusion 161. Employing thisconfiguration further increases the strength of the area around the baseof the first guide plate 131A.

(4-3)

As shown in FIGS. 17, 24A, and 24B, with the second rectilinear frame104, the first bayonet 162A and the second bayonet 162B are disposedaligned in the peripheral direction of the annular portion 130. The slit162C is formed between the first bayonet 162A and the second bayonet162B.

As shown in FIGS. 12, 24A, and 24B, the cam frame 103 has the cam framemain body 117 (cylindrical portion), a first portion 167A, a secondportion 167B, and an intermediate portion 167C. The first portion 167Aand the second portion 167B protrude inward from the inner peripheralface of the cam frame main body 117, and form the rotary guide grooves166. The intermediate portion 167C protrudes inward from the innerperipheral face of the cam frame main body 117 and is disposed betweenthe first portion 167A and the second portion 167B in the peripheraldirection. A first gap 167D is formed between the first portion 167A andthe intermediate portion 167C. The first gap 167D serves to lead thefirst bayonet 162A into the rotary guide grooves 166. A second gap 167Eis formed between the second portion 167B and the intermediate portion167C. The second gap 167E serves to lead the second bayonet 162B intothe rotary guide grooves 166. The length of the intermediate portion167C in the peripheral direction is less than the length of the slit162C in the peripheral direction.

As shown in FIGS. 24A and 24B, the first bayonet 162A and the secondbayonet 162B are guided into the rotary guide grooves 166 via the firstgap 167D and the second gap 167E. At this point the slit 162C passesthrough the intermediate portion 167C. When the first bayonet 162A andthe second bayonet 162B reach the rotary guide grooves 166, the secondrectilinear frame 104 is threaded to the cam frame 103. The firstbayonet 162A and the second bayonet 162B then move in the peripheraldirection through the rotary guide grooves 166. Consequently, the firstbayonet 162A hooks the first portion 167A, and the second bayonet 162Bhooks the intermediate portion 167C. Specifically, force exerted in theoptical axis direction on the second rectilinear frame 104 and the camframe 103 can be borne at two places on either side of the first guideplate 131A, and the first guide plate 131A is less apt to deform underforce exerted in the peripheral direction. Also, the first bayonet 162Ahooks the intermediate portion 167C. The same applies when the secondbayonet 162B hooks the second portion 167B. The second rotary guide 163side has the same configuration as the first rotary guide 162 side, andthe same effect is obtained.

Thus, with this lens barrel 100, the linking strength of the secondrectilinear frame 104 and the cam frame 103 can be increased.

(4-4)

As shown in FIGS. 17 and 18, since the first guide plate 131A protrudesin the optical axis direction from the inside of the inner peripheralprotrusion 161, the strength around the base of the first guide plate131A can be further increased by the inner peripheral protrusion 161.

(5-1)

As shown in FIGS. 14 to 16, when the first lens frame 101 and the camframe 103 rotate relatively, for example, after the front cam pins 122Ahave been guided by the front cam grooves 138A, the rear cam pins 122Bare guided by the rear cam grooves 138B, instead of the front cam pins122A and the front cam grooves 138A. Therefore, compared to when justthe front cam pins 122A and the front cam grooves 138A are provided, therelative movement distance in the optical axis direction between thefirst lens frame 101 and the cam frame 103 can be extended withoutincreasing the length of the first lens frame 101 and the cam frame 103in the optical axis direction. Therefore, the lens barrel 100 can bemade more compact while its zoom ratio is also raised. The front campins 122A is disposed in front of the rear cam pins 122B. The positionsof the front cam pins 122A and the rear cam pins 122B in the peripheraldirection are the same. As a result, the shape of the outer periphery ofthe cam frame 103 can be simplified, making it easier to product a moldfor cam pin-shaped parts in injection molding.

(6-1)

With this lens barrel 100, when the first lens frame 101 is guided inthe optical axis direction by the cam frame 103, as shown in FIGS. 22Aand 23A, part of the fixing portions 172 of the barrier unit 134 and thefirst lens frame 101 go into the cut-out spaces V formed in the camframe 103. Therefore, even if the first lens frame 101 and the cam frame103 are close together, interference can be prevented between the camframe 103 and the fixing portions 172 of the barrier unit 134 and thefirst lens frame 101.

(6-2)

As shown in FIG. 21, the barrier unit 134 can be easily mounted to thefirst lens frame 101 by hooking the mounting portions 134A of thebarrier case 173 to the projections 101B. Consequently, the structurefor attaching the barrier unit 134 to the first lens frame 101 can besimplified. Also, compared to when the barrier unit 134 is attached tothe first lens frame 101 with screws or the like, the dimensions of thefixing portions 172 can be smaller. Therefore, a more compact lensbarrel 100 can be obtained.

Other Embodiments

(A) In the above embodiment, the cam frame 103 was disposed on theinside of the first lens frame 101, but the cam frame 103 may bedisposed on the outside of the first lens frame 101.

(B) In the above embodiment, the cam followers 122, which were examplesof cam followers, and the reinforcing portions 137 were substantiallycylindrical in shape, but the cam followers may be elliptical or havesome other shape. The cam followers may be integrally molded from resin,or may be constituted by a member of metal or the like. The camfollowers may also be constituted by shafts and rollers.

(C) In the above embodiment, the second cam grooves 138 of the firstlens frame 101 need not be through-grooves, and may have a bottom.However, the second cam grooves 138 may be through-grooves. Having abottom, though, is preferable because it affords strength for holdingthe lenses.

(D) In the above embodiment, fourth cam grooves 125 are formed in theinner peripheral face of the cam frame main body 117. This is preferablebecause the cam frame 103 can be made thinner by not forming theauxiliary grooves 123 in the portion where the fourth cam grooves 125are formed.

Features of Embodiments

The features of the above embodiment are listed below. The inventionsencompassed by the above embodiment are not limited to what follows. Theparts given in parentheses after the various components and/or portionsare specific examples given to aid in an understanding of the features.The various components and/or portions are not limited to these specificexamples. Also, component and/or portion other than the describedfeatures may be modified or eliminated in order to obtain the effectsstated for the various features.

(1-1) The lens barrel pertaining to the first feature comprises a firstframe (fixed frame 107) and a second frame (cam frame 103). The firstframe has a plurality of cam grooves (first cam grooves 112A to 112C).The second frame has a plurality of cam followers (cam followers 119A to119C) and a gear portion (gear portion 120). The plurality of camfollowers are respectively inserted into the plurality of cam grooves.The gear portion transmits rotational force. The second frame transmitsthe rotational force to the gear portion, and thereby moves in theoptical axis direction while rotating with respect to the first frame.At least one of the plurality of cam followers is disposed on the imageplane side of the gear portion.

With this lens barrel, since at least one of the plurality of camfollowers is disposed on the image plane side of the gear portion of thesecond frame, the gear portion can be made longer in the peripheraldirection without increasing the spacing between the cam followers 119in the peripheral direction. Therefore, when the second frame isrotationally driven with respect to the first frame by the gear portion,large relative rotational angles between the first frame and secondframe can be ensured without sacrificing support accuracy of the camframe 103 with respect to the fixed frame 107. Thus increasing therelative rotational angles between the first frame and second frameallows the amount of movement of the second frame with respect to thefirst frame to be increased. That is, a higher zoom ratio can beachieved with this lens barrel.

(1-2) The lens barrel pertaining to the second feature is the lensbarrel pertaining to the first feature, wherein the plurality of camfollowers have a first cam follower, a second cam follower, and a thirdcam follower. The first cam follower is disposed on the image plane sideof the gear portion. Also, the first cam follower is disposed offset tothe image plane side with respect to the second and third cam followers.Therefore, the shape of the gear portion can be one that is straightalong the peripheral direction of the second frame.

(1-3) The lens barrel pertaining to the third feature is the lens barrelpertaining to the second feature, wherein when the first frame and thesecond frame rotate relatively, the first to third cam grooves guide thefirst to third cam followers respectively. As a result, the second framemoves in the optical axis direction while rotating with respect to thefirst frame. With this lens barrel, since the length of the first camfollower in the peripheral direction of the second frame is greater thanthe length of the first cam follower in the optical axis direction, thestrength of the first cam follower can be increased.

Meanwhile, if the length of the first cam follower is increased in theperipheral direction, the space between the first cam follower and thesecond cam follower will be narrower, for example. Accordingly, it willbe difficult to extend the length of the gear portion if the gearportion is disposed between the first cam follower and the second camfollower.

However, with this lens barrel, the first cam follower is disposed tothe rear of the first end (the first end 120A) of the gear portion.Accordingly, even though the length of the first cam follower isextended in the peripheral direction, the length of the gear portion canalso be extended in the peripheral direction. Therefore, employing theabove-mentioned configuration allows the impact resistance of the lensbarrel to be improved while also raising the zoom ratio.

(1-4) The lens barrel pertaining to the fourth feature is the lensbarrel pertaining to the second or third feature, wherein in a state inwhich the combined length of the first frame and the second frame isshortest, the first end of the gear portion meshes with a drive gear.The first cam follower is disposed on the image plane side of the firstend of the gear portion.

(1-5) The lens barrel pertaining to the fifth feature is the lens barrelpertaining to the fourth feature, wherein the gear portion has a secondend (second end 120B) disposed on the opposite side from the first end.The position of the second cam follower in the optical axis direction issubstantially the same as the position of the second end in the opticalaxis direction.

(1-6) The lens barrel pertaining to the sixth feature is the lens barrelpertaining to the fourth or fifth feature, wherein the length of thefirst end in the optical axis direction is less than the maximum lengthof the gear portion in the optical axis direction. This helps preventthe lens barrel from becoming larger in the optical axis direction eventhough the cam followers are disposed on the image plane side of thegear portion.

(1-7) The lens barrel pertaining to the third feature is the lens barrelpertaining to any of the second to sixth features, wherein the first camfollower is in contact with the gear portion. More specifically, the camfollower 119A is integral with the first end 120A of the gear portion120.

Consequently, the cam followers and the gear portion increase eachother's strength, and damage to both can be effectively prevented.

(1-8) The lens barrel pertaining to the eighth feature is the lensbarrel pertaining to the seventh feature, wherein a gap is formedbetween the second cam follower and the gear portion.

(2-1) The lens barrel pertaining to a ninth embodiment comprises amoving frame (first lens frame 101), a drive frame (cam frame 103), anda rectilinear guide frame (first rectilinear frame 102).

The moving frame has a substantially cylindrical moving frame main body(included in the first lens frame 101), rectilinear projections (firstguide protrusions 136A), a first cam mechanism (second cam grooves 138),and protrusions (protrusions 101C). The rectilinear projections protrudeoutward in the radial direction from the moving frame main body. Thefirst cam mechanism is provided to the inner peripheral face of themoving frame main body. The protrusions protrude to the image plane sidein the optical axis direction from the end of the moving frame mainbody.

The drive frame has a substantially cylindrical drive frame main body(cam frame main body 117) and a second cam mechanism (cam followers122). The second cam mechanism is provided to the outer peripheral faceof the drive frame main body and constitutes a cam mechanism (second camgrooves 138, cam followers 122) along with the first cam mechanism. Thisdrive frame uses a cam mechanism to guide the moving frame in theoptical axis direction. The rectilinear guide frame has rectilineargrooves (rectilinear guide grooves 128) that engage with the rectilinearprojections. The rectilinear guide frame supports the moving framerelatively rotatably and relatively movably in the optical axisdirection.

The drive frame has rotary guide portions (first bayonet couplers 121).The rotary guide portions support the rectilinear guide frame so that itcan rotate relatively with respect to the drive frame main body and doesnot move relatively in the optical axis direction. The rotary guideportions are disposed more to the outer peripheral side than the movingframe and on the outer peripheral side of the drive frame main body.

Also, the drive frame has a flange (flange 118) that protrudes outwardin the radial direction from the drive frame main body. The flange hasfirst insertion portions (recesses 150) and second insertion portions(through-holes 121C). The first insertion portions form a space intowhich at least part of the rectilinear protrusion enters. The secondinsertion portions form a space into which at least part of therectilinear protrusion enters.

With this drive frame, a space into which at least part of theprotrusions enters is formed. Also, a space into which at least part ofthe rectilinear projections enters is formed. Accordingly, part of themoving frame can be inserted into the holding space when the movingframe is guided by the drive frame in the optical axis direction.Specifically, the shortest combined length of the moving frame and thedrive frame in the optical axis direction can be reduced, allowing for amore compact lens barrel.

(2-2) The lens barrel pertaining to a tenth feature is the lens barrelpertaining to the ninth feature, wherein the drive frame further has aflange (flange 118) that protrudes outward in the radial direction fromthe drive frame main body. The flange has recesses that are recessed inthe optical axis direction. The recesses are first insertion portions. Arotary guide portion protrudes integrally in the optical axis directionfrom the flange.

(2-3) The lens barrel pertaining to an eleventh feature is the lensbarrel pertaining to the tenth feature, wherein the flange hasthrough-holes (through-holes 121C) disposed on the inner peripheral sideof the rotary guide portions. The through-holes 121C are disposed on theinner peripheral face of the first bayonet couplers 121. Thethrough-holes 121C are second insertion portions. At least part of theprotrusions can be inserted into the through-holes in the optical axisdirection.

(2-4) The lens barrel pertaining to a twelfth feature is the lens barrelpertaining to the ninth or tenth feature, wherein the rectilinear guideframe has rotary grooves (rotary grooves 175) that extend in theperipheral direction. The rotary guide portions have base portions (baseplates 121B) and guide protrusions (bayonets 121A). The base portionsextend along the peripheral direction of the cam mechanism, and protrudein the optical axis direction from the flange. The guide protrusionsprotrude outward from the base portions in the radial direction of thecam frame main body, and are inserted into rotary grooves.

(3-1) The lens barrel pertaining to a thirteenth feature comprises amoving frame (first lens frame 101), a drive frame (cam frame 103), anda rectilinear guide frame (first rectilinear frame 102). The movingframe has flange protrusions (first guide protrusions 136A). The driveframe uses a cam mechanism (cam mechanism M1) to guide the moving framein the optical axis direction. The rectilinear guide frame hasrectilinear grooves (rectilinear guide grooves 128) that are engagedwith the rectilinear projections. The rectilinear guide frame supportsthe moving frame so that it is able to move relatively in the opticalaxis direction, but does not rotate relatively. The drive frame has acam mechanism (cam frame main body 117) and a flange (flange 118). Thecam mechanism part (cam frame main body 117) constitutes a cammechanism. The flange (flange 118) protrudes outward in the radialdirection from the cam mechanism part. The flange has recesses (recesses150) which the rectilinear projections enter.

With this lens barrel, since the flange has recesses which therectilinear projections enter, the shortest combined length of themoving frame and the drive frame in the optical axis direction can bereduced. Therefore, the lens barrel can be made more compact.

(3-2) The lens barrel pertaining to a fourteenth feature is the lensbarrel pertaining to the thirteenth feature, wherein the recesses are aportion that is recessed in the optical axis direction.

(3-3) The lens barrel pertaining to a fifteenth feature is the lensbarrel pertaining to the thirteenth or fourteenth feature, wherein themoving frame further has a substantially cylindrical moving frame mainbody (main body portion 101A). The rectilinear projections protrudeoutward from the moving frame main body in the radial direction of themoving frame main body. The length of the distal ends of the rectilinearprojections in the optical axis direction is greater than the length ofthe bases of the rectilinear projections i the optical axis direction.Consequently, even if the rectilinear grooves are interrupted midway,the distal ends of the rectilinear projections can be moved stablywithin the rectilinear grooves. Therefore, this affords greater latitudein the design of the rectilinear guide frame.

(3-4) The lens barrel pertaining to a sixteenth feature is the lensbarrel pertaining to the fifteenth feature, wherein the length of therectilinear projections in the optical axis direction graduallyincreases toward the outside in the radial direction of the moving framemain body.

(3-5) The lens barrel pertaining to a seventeenth feature is the lensbarrel pertaining to any of the thirteenth to sixteenth features,wherein the distal ends of the rectilinear projections protrude moretoward the flange side than do the bases of the rectilinear projections.

When making the overall lens barrel more compact in the optical axisdirection is taken into account, it is preferable for the positions ofthe rectilinear projections to be on the opposite side from the subject.This is because the more the rectilinear projections are disposed on thesubject side, the smaller will be the amount of deployment of the movingframe with respect to the rectilinear guide frame.

Meanwhile, with this lens barrel, since the distal ends of therectilinear projections protrude more toward the flange than do thebases, the entire rectilinear projections can be disposed at positionsfar away from the subject. Furthermore, even though the distal ends ofthe rectilinear projections protrude more toward the flange than do thebases, when the rectilinear projections have moved closer to the flange,they can fit into the recesses. Therefore, the amount in which themoving frame is deployed with respect to the rectilinear guide frame canbe increased, while the size of the lens barrel can be further reduced.

(3-6) The lens barrel pertaining to an eighteenth feature is the lensbarrel pertaining to any of the thirteenth to sixteenth features,wherein the recesses are through-holes into which the rectilinearprojections can be inserted. When the recesses are through-holes, thishelps prevent the lens barrel from becoming larger even though therectilinear projections are made larger in the optical axis direction.

(4-1) The lens barrel pertaining to a nineteenth feature comprises afirst frame (shutter unit 106), a second frame (cam frame 103), and athird frame (second rectilinear frame 104). The first frame hasrectilinear guide grooves (rectilinear guide grooves 140). The secondframe uses a cam mechanism (cam mechanism M2) to guide the first framein the optical axis direction. The second frame has rotary guide grooves(rotary guide grooves 166) that extend in the peripheral direction. Thethird frame has an annular portion (annular portion 130), rectilinearguide portions (first guide plate 131A, second guide plate 131B), andbayonet portions (first rotary guide 162, second rotary guide 163). Therectilinear guide portions are provided to the inner peripheral part ofthe annular portion and extend in the optical axis direction. Thebayonet portions extend in the optical axis direction from the innerperipheral part of the annular portion.

With this lens barrel, the rectilinear guide portions of the third frameengage with the rectilinear guide grooves of the first frame, and thisresults in the first frame being supported so that it can moverelatively in the optical axis direction, but does not rotaterelatively. Also, the bayonet portions of the third frame engage withthe rotary guide grooves of the second frame, and this results in thesecond frame being supported so that it can rotate relatively withrespect to the third frame and can move relatively in the optical axisdirection. The bayonet portions protrude on both sides of the annularportion in the peripheral direction, past the rectilinear guideportions. The bayonet portions are supported by the second frame at twoor more places, including both sides of the rectilinear guide portionsin the peripheral direction.

With this lens barrel, the bayonet portions are provided to the innerperipheral part of the annular portion, and protrude on both sides inthe peripheral direction, past the rectilinear guide portions.Accordingly, the bayonet portions increase the strength of the areaaround the bases of the rectilinear guide portions. Therefore, even if aforce is exerted in the peripheral direction on the rectilinear guideportions, the rectilinear guide portions will tend not to be damaged.Furthermore, the bayonet portions are divided up into a plurality ofportions in the peripheral direction by slits. Accordingly, in a statein which the bayonet portions are engaged with the rotary guide groovesof the second frame, the bayonet portions will come into contact withthe second frame at more places. If the second frame supports at two ormore places including both sides of the rectilinear guide portions inthe peripheral direction, then the rectilinear guide portions will beless likely to deform under a force in the peripheral direction.Therefore, the linking strength of the second frame and third frame canbe increased. Thus, the overall strength can be increased with this lensbarrel.

(4-2) The lens barrel pertaining to a twentieth feature is the lensbarrel pertaining to the nineteenth feature, wherein the first regionsB1 and B2 occupied by the rectilinear guide portions in the peripheraldirection of the annular portion are disposed on the inside of thesecond regions B 11 and B 12 occupied by the bayonet portions in theperipheral direction of the annular portion.

(4-3) The lens barrel pertaining to a twenty-first feature is the lensbarrel pertaining to the nineteenth or twentieth feature, wherein theannular portion has a disk portion (disk portion 165) and a rib portion(inner peripheral protrusion 161). The rib portion protrudes in theoptical axis direction from the inner peripheral edge of the diskportion, and extends along the inner peripheral edge of the diskportion.

The bayonet portions have a first bayonet (first bayonet 162A, 163A) anda second bayonet (second bayonet 162B, 163B). The first bayonetprotrudes outward from the rib portion in the radial direction of theannular portion. The first bayonet is inserted into the rotary guidegrooves. The second bayonet protrudes outward from the rib portion inthe radial direction of the annular portion. The second bayonet isinserted into the rotary guide grooves.

With this lens barrel, since the annular portion has a rib portion, andthe bayonet portions have the first and second bayonets that protrudeoutward in the radial direction from the rib portion, it is easy toensure good strength around the bayonet portions.

(4-4) The lens barrel pertaining to a twenty-second feature is the lensbarrel pertaining to the twenty-first feature, wherein the first bayonetand the second bayonet are disposed aligned in the peripheral directionof the annular portion. A slit is formed between the first bayonet andthe second bayonet.

(4-5) The lens barrel pertaining to a twenty-third feature is the lensbarrel pertaining to the twenty-second feature, wherein the second framehas a cylindrical portion, a first portion, and an intermediate portion.The first portion protrudes inward from the inner peripheral face of thecylindrical portion, and forms the rotary guide grooves. Theintermediate portion protrudes inward from the inner peripheral face ofthe cylindrical portion, and is disposed between the first portion andthe second portion in the peripheral direction. A first gap forintroducing the first bayonet into the rotary guide grooves is formedbetween the first portion and the intermediate portion. A second gap forintroducing the second bayonet into the rotary guide grooves is formedbetween the second portion and the intermediate portion. The length ofthe intermediate portion in the peripheral direction is less than thelength of the slit in the peripheral direction.

When the first bayonet and the second bayonet are introduced into therotary guide grooves via the first gap and the second gap, theintermediate portion passes through the slit. When the first bayonet andthe second bayonet reach the rotary guide grooves, the third frame isthreaded to the first frame, and the first bayonet and the secondbayonet move through the rotary guide grooves in the peripheraldirection. Consequently, the first bayonet hooks the first portion, andthe second bayonet hooks the intermediate portion. Consequently, anyforce in the optical axis direction exerted on the first frame and thethird frame can be borne at two places. The same applies to when thefirst bayonet hooks the intermediate portion, and the second bayonethooks the second portion. Thus, with this lens barrel, the linkingstrength between the first frame and the third frame can be increased.

(4-6) The lens barrel pertaining to a twenty-sixth feature is the lensbarrel pertaining to any of the twenty-first to twenty-third features,wherein the rectilinear guide portions protrude in the optical axisdirection from the inside of the rib portion.

Consequently, the rib portion can be used to further raise the strengtharound the bases of the rectilinear guide portions.

(4-7) The lens barrel pertaining to a twenty-fifth feature is the lensbarrel pertaining to any of the twenty-first to twenty-fourth features,wherein the length of the first bayonet in the peripheral direction isgreater than the length of the slit in the peripheral direction. Thelength of the second bayonet in the peripheral direction is greater thanthe length of the slit in the peripheral direction.

(5-1) The lens barrel pertaining to a twenty-sixth feature comprises anouter frame (first lens frame 101) and an inner frame (cam frame 103).At least part of the outer frame forms the external appearance seen bythe user. The outer frame has at least one lens (first lens group G1)and a lens support (lens support 101D) that supports the lens. The lenssupport has recesses (101E) that are recessed in the optical axisdirection. Holes that go through in the optical axis direction may beused instead of the recesses 101E.

At least part of the inner frame is disposed on the inside of the outerframe. The inner frame uses a cam mechanism (cam mechanism M1) to guidethe outer frame in the optical axis direction. The inner frame has firstcam followers and second cam followers. The outer frame has first camgrooves that guide the first cam followers, and second cam grooves thatguide the second cam followers.

In this case, the lens barrel has a first state, a second state, and athird state during operation in which the outer frame and the innerframe are rotating relatively. In the first state, the first camfollowers (front cam pins 122A) are guided by first cam grooves (frontcam grooves 138A). In the second state, the first cam followers areguided by the first cam grooves, and the second cam followers (rear campins 122B) are guided by second cam grooves (rear cam grooves 138B). Inthe third state, the second cam followers are guided by the second camgrooves. In the third state, at least part of the first cam followersgoes into the spaces formed by the recesses (101E).

With this lens barrel, the lens barrel has a first state, a secondstate, and a third state during operation in which the outer frame andthe inner frame are rotating relatively. Therefore, compared to whenonly first cam followers and second cam grooves are provided, therelative movement distance of the outer frame and inner frame in theoptical axis direction can be extended without increasing the length ofthe outer frame or inner frame in the optical axis direction.Specifically, with this lens barrel, a higher zoom ratio can be achievedwhile minimizing an increase in size. The front cam pins 122A aredisposed in front of the rear cam pins 122B. The positions of the frontcam pins 122A and rear cam pins 122B in the peripheral direction are thesame. Thus, the shape of the outer periphery of the cam frame 103 can besimplified, and it is easier to produce a mold for the cam pin-shapedparts in injection molding.

(5-2) The lens barrel pertaining to a twenty-seventh feature comprisesan outer frame (first lens frame 101) and an inner frame (cam frame103). At least part of the outer frame forms the external appearanceseen by the user. The outer frame has at least one lens (first lensgroup G1) and a lens support (lens support 101D) that supports the lens.The lens support has recesses (101E) that are recessed in the opticalaxis direction. Holes that go through in the optical axis direction maybe used instead of the recesses 101E.

At least part of the inner frame is disposed on the inside of the outerframe. The inner frame uses a cam mechanism (cam mechanism M1) to guidethe outer frame in the optical axis direction. The inner frame has firstcam followers (front cam pins 122A) and second cam followers (rear campins 122B). The inner frame has first cam grooves (front cam grooves138A) that guide the first cam followers, and second cam grooves (rearcam grooves 138B) that guide the second cam followers.

In this case, the cam mechanism has a first state, a second state, and athird state during operation in which the outer frame and the innerframe are rotating relatively. In the first state, the first camfollowers are guided by first cam grooves. In the second state, thefirst cam followers are guided by the first cam grooves, and the secondcam followers are guided by second cam grooves. In the third state, thesecond cam followers are guided by the second cam grooves. In the thirdstate, at least part of the first cam grooves goes into the spacesformed by the recesses (101E).

With this lens barrel, the cam mechanism has a first state, a secondstate, and a third state during operation in which the outer frame andthe inner frame are rotating relatively. Therefore, compared to whenonly first cam followers and second cam grooves are provided, therelative movement distance of the outer frame and inner frame in theoptical axis direction can be extended without increasing the length ofthe outer frame or inner frame in the optical axis direction.Specifically, with this lens barrel, a higher zoom ratio can be achievedwhile minimizing an increase in size.

(5-3) The lens barrel pertaining to a twenty-eighth feature comprises anouter frame (first lens frame 101) and an inner frame (cam frame 103).At least part of the outer frame forms the external appearance seen bythe user. The outer frame has at least one lens (first lens group G1)and a lens support (lens support 101D) that supports the lens. At leastpart of the inner frame is disposed on the inside of the outer frame.The inner frame uses a cam mechanism (cam mechanism M1) to guide theouter frame in the optical axis direction.

The outer frame has first cam followers and first cam grooves. The innerframe has second cam grooves that guide the first cam followers, andsecond cam followers that are guided by the first cam grooves.

In this case, the cam mechanism has a first state, a second state, and athird state during operation in which the outer frame and the innerframe are rotating relatively. In the first state, the first camfollowers are guided by the second cam grooves. In the second state, thefirst cam followers are guided by the second cam grooves, and the secondcam followers are guided by first cam grooves. In the third state, thesecond cam followers are guided by the first cam grooves.

With this lens barrel, the cam mechanism has a first state, a secondstate, and a third state during operation in which the outer frame andthe inner frame are rotating relatively. Therefore, compared to whenonly first cam followers and second cam grooves are provided, therelative movement distance of the outer frame and inner frame in theoptical axis direction can be extended without increasing the length ofthe outer frame or inner frame in the optical axis direction.Specifically, with this lens barrel, a higher zoom ratio can be achievedwhile minimizing an increase in size.

(6-1) The lens barrel pertaining to a twenty-ninth feature comprises anfirst frame (first lens frame 101), a barrier mechanism (barrier unit134), and a second frame (cam frame 103). The barrier mechanism is fixedto the first frame and blocks off an opening. The second frame uses acam mechanism (cam mechanism M1) to guide the first frame in the opticalaxis direction. The second frame has a substantially cylindrical cammechanism (cam frame main body 117) and a thin-wall part (thin-wall part182) that is thinner than the cam mechanism. Fixing portions (fixingportions 172) of the barrier mechanism go into the spaces (cut-outspaces V) formed between the thin-wall part and the first frame.

With this lens barrel, the fixing portions of the barrier mechanism gointo spaces formed between the thin-wall part and the first frame.Accordingly, even when the first frame and the second frame move closetogether in the optical axis direction, the fixing portions can beprevented from interfering with the second frame. Consequently, withthis lens barrel, the minimum length of the first frame and second framein the optical axis direction can be shortened, and a more compact sizecan be obtained.

(6-2) The lens barrel pertaining to a thirtieth feature is the lensbarrel pertaining to the twenty-ninth feature, wherein the barriermechanism has barrier vanes (barrier vanes 135) that block off theopening, a barrier case (barrier case 173) that supports the barriervanes, and mounting portions (mounting portions 134A). The mountingportions constitute part of the fixing portions, and protrude in theoptical axis direction from the barrier case. The first frame has matesto the mounting portions. These mates (projections 101B) constitute partof the fixing portions, and hook the mounting portions. In this case,when the first frame is guided by the second frame in the optical axisdirection, at least part of the mounting portions and the mates to themounting portions goes into spaces (cut-out spaces V) formed between thethin-wall part and the first frame.

Thus, the barrier mechanism can be mounted to the first support frame byhooking the mounting portions to the fixing projections. Consequently,the configuration for attaching the barrier mechanism to the firstsupport frame can be simplified. Also, the size of the fixing portioncan be reduced as compared to when the attachment is by screws or thelike. Therefore, the lens barrel can be made more compact.

General Interpretation of Terms

In understanding the scope of the present disclosure, the term“comprising” and its derivatives, as used herein, are intended to beopen ended terms that specify the presence of the stated features,elements, components, portions, groups, integers, and/or steps, but donot exclude the presence of other unstated features, elements,components, portions, groups, integers and/or steps. The foregoing alsoapplies to words having similar meanings such as the terms, “including”,“having” and their derivatives. Also, the terms “part,” “section,”“portion,” “member” or “element” when used in the singular can have thedual meaning of a single part or a plurality of parts. Also as usedherein to describe the above embodiment(s), the following directionalterms “forward”, “rearward”, “above”, “downward”, “vertical”,“horizontal”, “below” and “transverse” as well as any other similardirectional terms refer to those directions of the lens barrel.Accordingly, these terms, as utilized to describe the present technologyshould be interpreted relative to the lens barrel.

The term “configured” as used herein to describe a component, portion,section, or part of a device implies the existence of other unclaimed orunmentioned components, portions, sections, members or parts of thedevice to carry out a desired function.

The terms of degree such as “substantially”, “about” and “approximately”as used herein mean a reasonable amount of deviation of the modifiedterm such that the end result is not significantly changed.

While only selected embodiments have been chosen to illustrate thepresent technology, it will be apparent to those skilled in the art fromthis disclosure that various changes and modifications can be madeherein without departing from the scope of the technology as defined inthe appended claims. For example, the size, shape, location ororientation of the various components and/or portions can be changed asneeded and/or desired. Components and/or portions that are showndirectly connected or contacting each other can have intermediatestructures disposed between them. The functions of one element can beperformed by two, and vice versa. The structures and functions of oneembodiment can be adopted in another embodiment. It is not necessary forall advantages to be present in a particular embodiment at the sametime. Every feature which is unique from the prior art, alone or incombination with other features, also should be considered a separatedescription of further technologies by the applicant, including thestructural and/or functional concepts embodied by such feature(s). Thus,the foregoing descriptions of the embodiments according to the presenttechnologies are provided for illustration only, and not for the purposeof limiting the technology as defined by the appended claims and theirequivalents.

INDUSTRIAL APPLICABILITY

The technology disclosed herein can be utilized as a lens barrel used indigital cameras, film cameras, portable telephones, projectors, andother such devices having projecting optical systems.

What is claimed is:
 1. A lens barrel, comprising: a first frameincluding a plurality of cam grooves; and a second frame including aplurality of cam followers that engage with each of the plurality of camgrooves, and a gear portion; wherein the second frame is configured tomove in the optical axis direction while rotating with respect to thefirst frame if rotational force is transmitted to the gear portion, andat least one of the plurality of cam followers is disposed on the imageplane side of the gear portion.
 2. The lens barrel according to claim 1,wherein: the plurality of cam followers includes a first cam follower, asecond cam follower, and a third cam follower; wherein the first camfollower is disposed on the image plane side of the gear portion and isdisposed offset to the image plane side with respect to the second andthird cam followers.
 3. The lens barrel according to claim 2, wherein:the plurality of cam grooves includes a first cam groove, a second camgroove, and a third cam groove; wherein the first, second, and third camgrooves guide the first, second, and third cam followers respectively,if the first frame and the second frame rotate relatively, so that thesecond frame moves in the optical axis direction while rotating withrespect to the first frame, and the length of the first cam follower inthe peripheral direction of the second frame is greater than the lengthof the first cam follower in the optical axis direction.
 4. The lensbarrel according to claim 2, wherein: a first end of the gear portionmeshes with a drive gear, in a state in which the combined axial lengthof the first frame and the second frame is shortest, and the first camfollower is disposed on the image plane side of the first end of thegear portion.
 5. The lens barrel according to claim 4, wherein: the gearportion includes a second end disposed on the opposite side from thefirst end, and the position of the second cam follower in the opticalaxis direction is substantially the same as the position of the secondend in the optical axis direction.
 6. The lens barrel according to claim4, wherein: the length of the first end in the optical axis direction isless than the maximum length of the gear portion in the optical axisdirection.
 7. The lens barrel according to claim 2, wherein: the firstcam follower is in contact with the gear portion.
 8. The lens barrelaccording to claim 7, Wherein: a gap is formed between the second camfollower and the gear portion.